diff --git a/src/wp-includes/class-wp-user-query.php b/src/wp-includes/class-wp-user-query.php
index 330882494e..8fc1564bef 100644
--- a/src/wp-includes/class-wp-user-query.php
+++ b/src/wp-includes/class-wp-user-query.php
@@ -776,6 +776,18 @@ class WP_User_Query {
 	public function query() {
 		global $wpdb;
 
+		if ( ! did_action( 'plugins_loaded' ) ) {
+			_doing_it_wrong(
+				'WP_User_Query::query',
+				sprintf(
+				/* translators: %s: plugins_loaded */
+					__( 'User queries should not be run before the %s hook.' ),
+					'<code>plugins_loaded</code>'
+				),
+				'6.1.1'
+			);
+		}
+
 		$qv =& $this->query_vars;
 
 		/**
@@ -840,7 +852,9 @@ class WP_User_Query {
 				$result->id = $result->ID;
 			}
 		} elseif ( 'all_with_meta' === $qv['fields'] || 'all' === $qv['fields'] ) {
-			cache_users( $this->results );
+			if ( function_exists( 'cache_users' ) ) {
+				cache_users( $this->results );
+			}
 
 			$r = array();
 			foreach ( $this->results as $userid ) {